Memory leak when use Tcl_Eval functions in C programming

In my C program, I use the tcl scripting for calculation. I use
Tcl_Eval and Tcl_EvalFile to execute the calculation and these
functions will return the result through tcl interpreter defined in C
code. However, since the tcl calculation is so much, I found in the
windows task manager that the program keeps on consumming the memory,
when every time it eval the tcl command or tcl script through Tcl_Eval
or Tcl_EvalFile.